Maintaining control of fluid pressures experienced within a wellhead equipment requires proper sealing around the tubular elements in the wellhead equipment. Thus, various types of annular seals which seal around tubular elements have been developed over the years. These seals typically fall under one of three categories: elastomer, elastomer combined with metal, or metal seals.
Permanently-installed wellhead equipment requires seals that retain high sealing integrity when exposed to extreme pressures, or pressure fluctuations, extreme temperatures or temperature fluctuations, corrosive fluids, and dirt. Elastomer materials may break down when exposed to extreme temperature or corrosive fluids. As a result, metal seals are typically the preferred type of seal since they do not share the temperature sensitivity problems of elastomeric materials. The metal seals can be made from high-strength, corrosion-resistant materials which resist physical damage and corrosion.